Who turns the river green?

On St. Patricks's Day weekend, the green river dyeing is a party for all of Chicago, but the process itself is a family affair for the Chicago Plumbers Local 130 UA.

Since the Union began dyeing the river in 1962, the tradition has been passed down in the Butler and Ronan families, who get the privilege of administering the dye each year.

"It's in the third generation right now," said Bill King, 60, who helps monitor the shore and the website for the event. "These guys' grandfather was actually the one who first started it."

When the dyeing did start, it was hardly an event at all. Plumbers used the dye to find leaks or trace the paths of water flowing into the river, King said. They knew that if they had enough dye, they could change the river's complexion, and one year, just decided to do so.

"They just hopped on a boat and went out and did it. Now it's become a Chicago thing," he said.

"Enough dye" means 40 pounds in this case, and it takes about 15 minutes to distribute it all. The process starts at Columbus Drive with two boats: one throws the dye out near the motors while the other trails it and stirs the dye around. The boats conclude at Wabash Avenue, although the stirring boat will make another lap if the dye isn't well-distributed.

King called the dye "some very potent stuff," and said it takes a few showers to wash it off. The dye itself doesn't begin as green, but as orange. It turns green once it hits the water and dissipates over time. King couldn't say what the color does to the fish in the water, but he does know that it doesn't harm them.

"The original type of dye was outlawed about 25 years ago. It was toxic, so we had to develop something new," he said. "Now it's a vegetable-based dye. It's harmless."

With last year's warm weather, King said the dyeing was one of the most packed events the Union had ever seen. Police estimates indicate between 30,000 and 40,000 people attend the dyeing, and King said he hopes it's similarly popular this year (the dyeing begins at 10 a.m.), as they're part of a contest with WXRT to see who gets to throw the first dye in the river. He's proud that it's become a Chicago tradition, one that they're not eager to share with anyone.

"We've had contacts from Turkey and Denmark on the website trying to do it, but we don't want to share ideas," he said. "It's a unique Chicago thing, and if they were doing it over there, it wouldn't be unique."